The present invention relates to carburetors for internal combustion engines, and more particularly, to primary and secondary fuel delivery circuits therefor and methods for the operation and installation of same.
According to one aspect of the present invention, a carburetor including a chamber for receiving and holding fuel, a sidewall forming a passageway for the flow of air therethrough having an inlet opening and an outlet opening and a constricted portion therebetween further includes a plurality of orifices at different locations adjacent to the sidewall in communication with the air flow passageway, and connecting passages connecting the orifices with the fuel chamber. The various orifices are positioned at different locations in the air flow passageway such that different air flow conditions through the air flow passageway will generate different negative pressure conditions in the respective orifices and connecting passages, such that fuel will be drawn to the air flow passageway through the orifice or orifices and connecting passage or passages with the greatest negative pressure conditions therein, the operational result being fuel delivery capable or rapidly changing corresponding to rapidly changing air flow conditions in the air flow passageway corresponding to changing operating conditions.
According to another aspect of the present invention, the carburetor has a primary fuel delivery circuit including a primary fuel passage extending from the fuel holding chamber to a primary fuel delivery orifice located in communication with the air flow passageway. At least one secondary fuel delivery circuit is providing including at least one orifice in communication with the air flow passageway adjacent to the carburetor sidewall. At least one connecting passage communicates the at least one orifice with the primary fuel delivery circuit. In operation, different air flow conditions through the air flow passageway will generate different negative pressure conditions in the various orifices, under some air flow conditions fuel being drawn into the primary fuel delivery circuit by the negative pressure conditions and exiting into the air flow passageway through the orifices and connecting passageways having the greater negative pressure conditions therein, the fuel delivery characteristics being rapidly changeable corresponding to changing air flow conditions.
The circuitry according to the present invention can be easily and readily installed on a wide variety of known carburetor construction, and in new carburetor constructions.
In operation, it has been observed that the fuel exiting the orifices into the air flow passageway is in a highly vaporized state, which in combination with the ability of the fuel delivery to rapidly change corresponding to changes in air flow conditions, provides enhanced engine performance and response.